1. Field of the Invention
Embodiments of the present invention generally relate to tracking suitably-equipped mobile objects such as a person, an animal, or a mobile apparatus, in a building. More specifically, embodiments of the present invention relate to a system and method for tracking the location of emergency responders in a multi-story building, and reporting the locations to one or more monitoring stations, by use of a transponder.
2. Description of the Related Art
Knowing the physical locations of one or more persons, such as the locations of emergency responders who are responding to an emergency, is often of keen interest. For instance, firefighters fighting a fire, or a monitoring station such as a command site responsible for directing the firefighters, may need to know the location of each firefighter in real time, in order to direct firefighter resources for fire suppression, rescue of a victim, rescue of the first responder, rescue of fellow first responders, danger avoidance, and so forth. Time may be of the essence in such situations. The problem of locating each firefighter is made difficult by the environment, including poor visibility from the presence of smoke and lack of lighting or the failure of lighting, heat or the fire itself, debris and/or collapsing structure caused by the fire, noxious fumes emitted by burning materials, lack of oxygen, and so forth. This problem may be exacerbated in multilevel structures such as office buildings, large apartment buildings, etc., in which the firefighters may be spread across multiple floors, or in which certain floors such as subbasements or upper levels of tall buildings may have limited transmission range.
The problem of locating and/or tracking first responders in real time may also be applicable to police and/or SWAT responders, who may be called upon to hunt for a criminal in a large building, although such an environment may not be as hostile as a firefighting environment.
Various schemes have been contemplated to address the problem of locating firefighters. Some fire departments have been working to develop an accountability system that would more effectively pinpoint, track, and record the locations of firefighters and equipment. Having a record of the positions of firefighters while fighting a fire may also be useful during post-event training in order to illustrate examples of tactics or strategies that were either effective or not effective. The goal of tracking mayday calls more precisely is one of several initiatives that some fire departments have undertaken as part of an overall strategy that relies on data to increase awareness and communication in emergencies, when hundreds of people may be converging at once, such as in a large urban office building.
Mayday radio systems and associated software are available that broadcast which first responders may be in need of help. However, such systems and software do not address the problem of determining the location of a first responder with enough precision to direct the movement of the first responder or the co-responders to a safe position or a position where they may be needed, particularly in large, multi-story buildings in which the location problem becomes three-dimensional. For example, it would be useful to know the location of a trapped firefighter on a three-dimensional diagram with a relatively exact location of where he or she is trapped.
Other systems known in the art include disposable elements that together create a mesh-like communication system. The disposable elements create an electronic “breadcrumb” through which it may be possible to determine the location of a particular emergency responder. A disadvantage of such systems is that many response situations do not turn out to be emergency situations, and in those cases the disposable elements are wasted and may present a nuisance for a property owner to clean up. Another disadvantage is that the disposable elements are not always reliable and should one or more fail, it compromises the effectiveness of the overall mesh system.
Yet another approach to tracking known in the art is to have a first responder wear a tracking device such as in a boot. The tracking device will keep track of motion in three dimensions and radio back a position that is calculated by dead reckoning principles. The tracking device may also include additional sensors such as a barometer that may indicate altitude. A disadvantage of such systems is that positional errors of inertial navigation systems increase over time, and barometric readings may become inaccurate if air pressure changes inside a building due to a fire becoming sufficiently large.
Yet another approach to tracking known in the art is to use triangulation or electromagnetic field strength properties of the radio waves. However, radio waves inside a building may experience multiple reflections, making such a triangulation or field strength approach difficult to implement.
Yet another approach to tracking known in the art is to use a motion detector to detect a lack of motion. Once a lack of motion is detected, an audible signal is emitted. Disadvantages of this approach include hearing the audible signal sufficiently well in a noisy environment, dependence upon direction-finding by the human ear, blockage of audible signals such as between floors, acoustic reflections, and so forth.
The known art may be adequate for small structures, but is inadequate for the large, multi-story structures that typically house large companies. The structures often include a robust communication structure such as Ethernet access and/or WiFi or other wireless access technologies. Therefore, there is a need for an improved position locating method and system in order to overcome the shortcomings of the known art for large, multi-story structures.